As of right now you can't set custom textures provided by hardlinker to the card face.
The way cards like this and this have it is by replacing the texture and renaming the material in the model. In principle it can be automated by using SB3UtilityScript.exe included with SB3U. The catch might be that the index of the texture might be different for different skirts.
Once you implement the plugin system I'll try to include the necessary data into the hardlinker plugin. Please implement the ability to run SB3U scripts as well (or if you can do it without it'll be even better).
Depending on how the plugin system works I might even do the Hair Highlighter plugin.
This is definitely out of scope of the next update though. Just something to keep in mind for when you're figuring out the plugin system